That article does not look correct to me.
The correct file location is...
C:\Program Files (x86)\IBM\Lotus\Notes\framework\rcp\deploy\jvm.properties
There are 2 setting to look at: The starting heap size (vmarg.Xms) and the maximum heap size (vmarg.Xmx).
We set both of these to 1 gig (as long as the user has more than a gig available.
Here are the default values...
vmarg.Xmx=-Xmx256m
vmarg.Xms=-Xms48m
We change them to...
vmarg.Xmx=-Xmx1024m
vmarg.Xms=-Xms1024m